Tag Archives: satellite

This image from the Solar Dynamics Observatory shows the X6.9 solar flare of Aug. 9, 2011 near the western limb (right edge) of the sun. CREDIT: NASA/SDO/Weather.com

Solar flares like the huge one that erupted on the sun early today (Aug. 9) will only become more common as our sun nears its maximum level of activity in 2013, scientists say.

Tuesday’s flare was the most powerful sun storm since 2006, and was rated an X6.9 on the three-class scale for solar storms (X-Class is strongest, with M-Class in the middle and C-Class being the weakest).

Flares such as this one could become the norm soon, though, as our sun’s 11-year cycle of magnetic activity ramps up, scientists explained. The sun is just coming out of a lull, and scientists expect the next peak of activity in 2013. The current cycle, called Solar Cycle 24, began in 2008.

“We still are on the upswing with this recent burst of activity,” said Phil Chamberlin, a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., who is a deputy project scientist for the agency’s Solar Dynamics Observatory, a sun-studying satellite that launched in February 2010. “We could definitely in the next year or two see more events like this; there’s a potential to see larger events as well.”

A more active sun

Earth got lucky with the most recent flare, which wasn’t pointed directly at Earth; therefore, it didn’t send the brunt of its charged particles toward us, but out into space. However, we may not be so fortunate in the future, experts warned.

“We’re in the new cycle, it is building and we’ll see events like this one,” said Joe Kunches, a space scientist with the National Oceanic and Atmospheric Administration (NOAA)’s Space Weather Prediction Center. “They’ll be much more commonplace and we’ll get more used to them.”

Spacecraft such as the Solar Dynamics Observatory (SDO), which recorded amazing videos of the Aug. 9 solar flare, and other observatories will be vital in monitoring the sun during its active phase, researchers said.

How sun storms form

Storms brew on the sun when pent-up energy from tangled magnetic field lines is released in the form of light, heat and charged particles. This can create a brightening on the sun called a flare, and is also often accompanied by the release of a cloud of plasma called a coronal mass ejection (CME).

These ejections are the part we Earthlings have to worry about.

As the CME careens through space, it can send a horde of charged particles toward our planet that can damage satellites, endanger astronauts in orbit, and interfere with power systems, communications and other infrastructure on the ground.

“We’re well aware of the difficulties and challenges,” Kunches told SPACE.com. “We know more about the sun than we ever have.”

Can we predict solar storms?

When a big storm occurs, the Space Weather Prediction Center releases a warning to the U.S. Department of Homeland Security, emergency managers and agencies responsible for protecting power grids. Then power grids can distribute power and reduce their loads to protect themselves.

Satellite and power companies are also trying to design technology that can better withstand the higher radiation loads unleashed by solar storms.

Still, scientists would like to offer more advanced warnings when big storms are headed our way.

“We’re being reactive, we’re not being proactive,” Chamberlin said. “We don’t know how to predict these things, which would be nice.”

Chamberlin said solar science has come a long way in recent years, though, and the goal of SDO and other NASA projects is to improve our understanding of the sun and our ability to forecast space weather.

You can follow SPACE.com senior writer Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

Astronomers poring over 35 NASA Hubble Space Telescope images of the solar system’s farthest known object, unofficially named Sedna, are surprised that the object does not appear to have a companion moon of any substantial size.

This unexpected result might offer new clues to the origin and evolution of objects on the far edge of the solar system.

When Sedna’s existence was announced on March 15, its discoverer, Mike Brown of Caltech, was so convinced it had a satellite that an artist’s concept of Sedna released to the media included a hypothetical moon.

Brown’s prediction was based on the fact that Sedna appears to have a very slow rotation that could best be explained by the gravitational tug of a companion object. Almost all other solitary bodies in the solar system complete a spin in a matter of hours.

“I’m completely baffled at the absence of a moon,” says Brown. “This is outside the realm of expectation and makes Sedna even more interesting. But I simply don’t know what it means.”

Immediately following the announcement of the discovery of Sedna, astronomers turned the Hubble Space Telescope toward the new planetoid to search for the expected companion moon. The space-based platform provides the resolving power needed to make such precision measurements in visible light. “Sedna’s image isn’t stable enough in ground-based telescopes,” says Brown.

Surprisingly, the Hubble images taken March 16 with the new Advanced Camera for Surveys only show the single object Sedna, along with a faint, very distant background star in the same field of view.

“Despite HST’s crisp view (equivalent to trying to see a soccer ball 900 miles away), it still cannot resolve the disk of mysterious Sedna,” says Brown. This would place an upper limit in the object’s size of being approximately three-quarters the diameter of Pluto, or about 1,000 miles across.

But Brown predicted that a satellite would pop up as a companion “dot” in Hubble’s precise view. The object is not there, though there is a very small chance it might have been behind Sedna or transiting in front of it, so that it could not be seen separately from Sedna itself in the Hubble images.

Brown based this prediction on his earlier observations of apparent periodic changes in light reflecting from Sedna’s mottled surface. The resulting light curve gives a long rotation period exceeding 20 days (but not greater than 50 days). If true, Sedna would be the slowest rotating object in the solar system after Mercury and Venus, whose slow rotation rates are due to the tidal influence of the Sun.

One easy way out of this dilemma is the possibility that the rotation period is not as slow as the astronomers thought. But even with a careful reanalysis the team remains convinced that the period is correct. Brown admits, “I’m completely lost for an explanation as to why the object rotates so slowly.”

Small bodies like asteroids and comets typically complete one rotation in a matter of hours. Pluto’s rotation has been slowed to a relatively leisurely six-day period because Pluto is tidally locked to the revolution period of its satellite Charon. Hubble easily resolves Pluto and Charon as two separate bodies. NASA’s forthcoming James Webb Space Telescope will provide a platform for further high-resolution studies of the infrared light from such distant, cold bodies in our solar system.

The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

Russia plans to send a satellite with a radio beacon to near-Earth asteroid of 99942 Apophis for finding out how big is a threat of its collision with Earth, the country’s Academy of Sciences said in its report on 7 April.

The asteroid is considered by the Russian scientists as the most serious threat to Earth as for now.

In 2029, Apophis will be at a distance of only about 36,000 miles to our planet, at the height of the orbits of geostationary satellites. The asteroid could change its orbit and cannon Earth in 2036.

The core target of the possible mission will be to clarify the exact trajectory of Apophis for up to 2036. The satellite will be equipped with a radioisotope power source with a buffer battery.

“From technical point of view the mission could be started for implementation from 2015,” the Academy said in the report.